May 18, 2024


Cool & Filtered news from the worlds of RC Racing

We’re restoring a Losi XX CR Kinwald – Part II Front End

If you have been reading Part I of this series, you will know that I have a shabby Losi XX CR Kinwald needing some tlc.

Here’s a link to Part I –

We worked out most of the parts needed, and have repaired and anodized some of the parts. The car has been stripped and I have cleaned each part carefully. So now that you’re all caught up lets continue…..

Episode: 7

Is it time to start this vintage RC build?

Yes it is!

14th February 2021 – The final few parts arrived here this week which allows the build to get underway. The steering bellcranks, front brace and battery foams were all needed, I bought the rest of the items just to make sure the car was as close to perfect as possible.

Normally when building a new kit, I will build the diffs and shocks first. I find it stops you doing the most mundane tasks at the end of the build when you are tired – this is when mistakes can be made. With this build I’m following the manual…..

So lets get going…..

Front bulkhead assembly.

Losi XX CR Kinwald – Page 1

It was a delight to pick up the first few pieces and assemble them. I’ve examined each piece, cleaned, repaired, replaced but not actually put them together.

Everything fits perfectly. None of the screws overtightened, just “nipped”. The hinge pin slid in nicely too – we’re off to a good start.

I built up the sub- assembly and added the shock mounts. I would notice my first mistake later on as I’d selected a shock mount screw which were a couple of mm too long.

For the next step the front end sub-assembly is offered up to the chassis plate.

Front bulkhead ready to fit

Again, everything fitting perfectly.

Steering knuckles

The manual then takes you away from what you’ve built so far to concentrate on the two front outboard components.

The steering knuckles are new. It was hard to find a complete set of kit 25 degree knuckles and uprights. I eventually got the parts individually. They are the kind of item where someone buys the set to replace just one component – I was glad to get them.

Top tip: I put a drop of threadlock on the long screw earlier in the week and let it fully dry. I prefer to dry-lock these screws as wet-lock can be tricky to remove. Normally the screw head becomes damaged.

The bearings are original Losi items. Cleaned and oiled.

The stub axles are still a snug fit even though I had used a bit of 1200 sandpaper and drill to clean them. It would have been easy to remove too much material and create a problem.

front knuckles and axles assembled

With the knuckles built, the next task is to assemble them onto the 25 degree uprights.

Both the kingpin and the outer hingepin on the Losi XX CR Kinwald have a very small area cross section in comparison to modern cars. They are prone to bending. The best way to check them is to plate each pin on a flat surface, like a setup board, and elevate it slightly at one end. The pin should roll – accelerating linearly. If the pin wobbles or stops rolling, its probably bent.

Bringing the front end together

I checked the kingpins and they are fine. I have a mix of new and clean used e-clips for the pins. The e-clips fit the pins well, and the pin is a tight fit into the knuckle. I expected this as the knuckles were new.

Assembling the Losi XX front end

The next step is to put the chassis and outboard subassemblies together. I put the hinge pins into a drill chuck and used a microfibre cloth and fine metal polish to clean them. I didn’t want to polish them too much as they would become too shiny, I just wanted to achieve the kit finish.

The parts all went together perfectly. Again I’m using a mix of new and very clean used e-clips. The front brace only arrived this week from the USA. It was surprising as to how much strain has to go into the plastic brace before the hingepins will slide through.

The next step is to put the tierod together and onto the car. I found it hard to get a set of new grey rod ends. I eventually put together a set by buying ball stud sets which came with just 4 rod ends. So three packs gave me the 12 required.

With the tie rods fitted the car’s front end is starting to take shape.

Front suspension just awaiting the shocks

It’s important at this stage to check the free movement of the suspension arms. Everything should be free to move and not stick at any point in the travel of the arm.

Steering bellcranks

Losi XX CR Kinwald GenII steering parts

Now we move onto the steering assembly. The GenII steering system on this car is different to the original steering on the early cars. It is important when building the servo saver to set it correctly – fully tightened down and then 2 turns back.

Losi XX GENII Servo Saver bellcrank

The lay bellcrank sits on a shaft, which is the same as the outboard kingpins. Check that it is straight.

The drive and lay bellcranks

The steering system sits on tiny ball bearings. The bearings sit into recesses in the chassis plate which can trap moisture/water so that the bearing corrodes. I have replaced these with brand new bearings.

The assembly is retained by a plastic moulding – number 41 in the photo above.

Keep it tidy.

This piece often can with area of rough flashing on it. The one I have is new and is suffering from this. A scalpel or x-acto knife will remove this flashing. You must have free steering movement with the two top screws fully tightened down.

The centre link length must be very accurately set. There are plenty of parallel lines on the chassis in that area to help you get it just right.

The steering system just needs a servo and tie rods to be complete.

Steering Servo

The tie rods fit easily, bringing us another step closer. The servo must be modified to fit the Losi XX CR Kinwald. Half of each servo lug has to be removed and the offset mountings aligned specifically for your brand and model of servo.

I happen to have a vintage 6v KO FET servo which is listed on the manual, so it is a good fit and easy to select the correct alignment.

Vintage 6v KO servo missing its stepdown resistor, for now.

The servo is clamped into position with a graphite plate.

This plate is held down with two dedicated screws and it shares two screws with the main front plate which supports the whole front end.

The Losi narrow washers which came on the car had lost most of their gold anodized colouring, so we’ve installed new ones.

Losi XX CR Kinwald with a nearly complete front end.

The front end is nearly fully built, it just needs shocks, front skid plate and wheels.

We will leave it there for Part II. Part III – rear end will be next week.